Electronic Flora of South Australia Genus Fact Sheet

Genus ECTOCARPUS Lyngbye 1819: 130, nom. cons.

Phylum Phaeophyta – Order Ectocarpales

Thallus filamentous, uniseriate, much branched, with most branches tapering gradually to a false hair; phaeophycean hairs absent. Growth diffuse. Cells with several elongate, ribbon-like phaeoplasts, simple or branched and usually relatively broad in relation to the cell, and each with several pyrenoids; physodes usually present.

Reproduction: Reproduction by unilocular (meio-) sporangia, neutral plurilocular sporangia and by plurilocular gametangia, all usually pedicellate; generations isomorphic; many species or plants reproducing largely by the neutral sporangia.

Lectotype species: E. siliculosus (Dillwyn) Lyngbye 1819: 131, pl. 43B,C.

Taxonomic notes: A common genus credited with numerous species, many of which are probably synonyms (Russell 1966). Two species only are here recognised on southern Australian coasts, following the study of Russell. The complex reproductive cycle of E. siliculosus is described by Müller (1967).

References:

LYNGBYE, H.CH. (1819). Tentamen Hydrophytologiae Danicae. (Copenhagen.) McCULLY, M.E. (1966). Histological studies on the genus Fucus I. Light microscopy of the mature vegetative plant. Protoplasma 62, 287–305, Fig. 1. MacLENNAN, I.G. (1956). A brown alga (Petrospongium rugosum) new to Victoria. Proc. R. Soc. Vict. 69, 1–3.

MÜLLER, D.G. (1967). Generationswechsel, Kernphasenwechsel and Sexualität der Braunalge Ectocarpus siliculosus im Kulturversuch. Planta 75, 39–54.

RUSSELL, G. (1966). The genus Ectocarpus in Britain. I. The attached forms. J. mar. biol. Ass. U.K. 46, 267–294.

The Marine Benthic Flora of Southern Australia Part II complete list of references.

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (14 December, 1987)
The Marine Benthic Flora of Southern Australia
Part II
©Board of the Botanic Gardens and State Herbarium, Government of South Australia

KEY TO SPECIES OF ECTOCARPUS

1. Thallus much branched from near the base and above, main branches subdichotomous to irregular, without fascicles of branches; plurilocular sporangia elongate, scattered, usually not in series

E. siliculosus

1. Thallus with well developed axes from a clumped base, usually bare below with short fasciculate laterals above, branchlets often curved; plurilocular sporangia elongate-ovoid to tapering, often in series of 2–4 on axes or branchlets

E. fasciculatus


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